Global estimates of suitable areas for marine algae farming

Abstract

Marine algae, both macro and micro, have gained increasing attention for their numerous ecosystem service functions, such as food and raw materials provision and climate change mitigation. Currently, the practice of large-scale algae farming is limited to Asian waters, but significant interest has arisen from other continents. However, there is a lack of knowledge about the areas with suitable environmental conditions for expanding algae farming on a global scale. Previous studies have primarily focused on nutrient availability and thermal constraints when assessing the potential for algae culture. This study uses species distribution models based on an ensemble consensus approach to determine the extent of suitable areas and takes into account multiple environmental factors that may affect the feasibility of algae culture. Our results show that approximately 20.8 million km2 of the ocean (∼13.8% of the economic exclusive zones) is suitable for farming marine algae species, with most potential areas located near the coastline. Surprisingly, four out of the top five countries with the largest area suitable for seaweed farming, including Australia, Russia, Canada, and the US, account for 30% of the total suitable areas, yet they currently produce less than 1% of the global seaweed. Several species show promising characteristics for large-scale cultivation, but their viability for commercial production remains uncertain and subject to further assessment of economic feasibility and social acceptance. Further research on the ecological benefits of seaweed farming could also promote the development of an ecologically friendly and financially viable algae mariculture industry. This study provides a scientific basis for decision-makers to understand potential expansion areas and feasible pathways for seaweed farming, with the ultimate goal of ensuring the sustainable utilization of marine resources.